BRPI0815737B1 - "METHODS FOR THE PRODUCTION OF AN AMORPHAL COMPOSITION OF SILICA-ALUMINA" - Google Patents

Description

(54) Title: METHODS FOR THE PRODUCTION OF AN AMORPHAL COMPOSITION OF SÍLICAALUMINA (51) Int.CI .: B01J 21/12; B01J 23/44; B01J 35/10 (30) Unionist Priority: 8/27/2007 US 60 / 968,129 (73) Holder (s): SHELL INTERNATIONALE RESEARCH MAASCHAPPIJ B.V (72) Inventor (s): RUSSELL CRAIG ACKERMAN; CHRISTIAN GABRIEL MICHEL; JOHN ANTHONY SMEGAL; JOHANNES ANTHONIUS ROBERT VAN VEEN

1/22 “METHODS FOR THE PRODUCTION OF AN AMORPHAL COMPOSITION OF SILICA-ALUMIN” [001] The current invention relates to an amorphous composition of silica-alumina and a method of producing such a composition.

[002] The prior art presents numerous methods of producing amorphous silicaalumina and it is recognized that the physical and catalytic properties of amorphous silicaalumina can be highly dependent on the method by which it is manufactured. For example, US patent number 4,289,653 teaches that the properties of silica-alumina are highly dependent on the way in which it is manufactured, and shows a method of preparing silica-alumina compositions. The method presented includes the preparation of silica-alumina by mixing an alkali metal silicate (eg, sodium silicate) with an aluminum salt (eg, aluminum sulfate) and a mineral acid to form an acidulated solution. A basic precipitate, such as ammonium hydroxide, is then added to the acidulated solution to raise its pH and thereby cogelify the silica and alumina species. The resulting cogelified mass of the silica-alumina hydrogel is recovered from the solution and used in the preparation of nitrification catalysts and other hydroprocessing containing group VI and group VIII metals.

[003] American patent number 4,499,197 teaches another method of producing a silica-alumina composition. This patent teaches the manufacture of silica-alumina cogel by reacting a solution of alkali metal aluminate (sodium aluminate) with a solution of alkali metal silicate (sodium silicate) to obtain a pre-gelled mixture of the silica reaction -alumina having a pH of 12 to 12.5. The pre-gel is then mixed with an aluminum salt (aluminum sulfate) and an acidified rare earth solution, and, after aging, the resulting cogel is recovered. The amorphous silica-alumina cogels of the ‘197 patent

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2/22 may have a silica content of 10 to 90% by weight. Cogels are characterized as having a surface area of 100 to 400 m ² / g with about 30 to 60% of their surface area that is contained in the pores having a diameter of about 40 to 100 angstroms.

[004] American patent number 4,988,659 discloses a silica-alumina cogel and a method of producing such a cogel. The cogel is made by adding a silicate solution in an aqueous solution of an acid and an acid aluminum salt, such as aluminum chloride or aluminum sulfate, to form an acidulated silica solution having a pH in the range of 1 to 4 , followed by raising the pH of the solution by adding a base, aging the solution, and recovering the resulting co gel. The recovered cogel can be further processed by using an acid to induce syneresis, washing, and then spray drying. The final dry cogel is used as a cracking catalyst, a support for hydrocracking applications and other uses.

[005] American patent number 6,872,685 shows an amorphous silica-alumina composition having a Si / Al surface-to-volume ratio (SB ratio) that is in the range of 0.7 to 1.3 and having less 10% of crystalline alumina phase present in the composition. Amorphous silica-alumina is prepared by mixing a solution of silicate (sodium silicate) and a solution of aluminum acid salt (aluminum sulfate) while maintaining the pH of the mixed solution in less than 3, followed by gradual addition of a basic precipitate in the mixed solution to produce a precipitated cogel that can be recovered, washed and spray dried. The cogel material can be used to produce a silica-alumina catalyst or a catalyst support.

[006] American patent number 6,872,685 teaches the use in numerous hydroconversion processing applications of compositions that include amorphous silica-alumina that are made, in general, by preparing a solution

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3/22 containing silica and alumina followed by gelation of the solution. The cogel can be used as a catalyst support material or it can be combined with other components in matrices. The cogel is used in hydrocracking, degreasing and hydro finishing.

[007] It is desirable to have an amorphous silica-alumina composition that has certain physical and catalytic properties, making it especially useful as a catalyst or a component of a catalyst for use in various hydroprocessing applications.

[008] It is also desirable to have a process for the preparation of amorphous silicaalumina having certain desired physical and catalytic properties.

[009] It is also desirable to have a reasonably simple and economical process for the manufacture of amorphous silica-alumina compositions, and especially, amorphous silica-alumina compositions having certain desired physical and catalytic properties.

[0010] Therefore, a new silica-alumina composition is presented which consists of amorphous silica-alumina having an A / B ratio (as defined here later) that exceeds 2.2. This silica-alumina composition can be made by combining within a mixing zone, water and aluminum sulfate, to produce a mixture having a pH in the range of 1.5 to 6.5; thereafter, increasing the pH of said mixture to within the range of 7.5 to 12, by adding sodium silicate to said mixture within said mixing zone; and recovering a precipitated solid from said mixture in said mixing zone, where said precipitated solid is composed of said silica-alumina composition.

[0011] In another embodiment of the method of the invention, a silica-alumina composition is prepared by producing a precipitated solid within a mixing zone, which consists of silica and alumina, by: (a) introducing water

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4/22 in said mixing zone; (b) introducing aluminum sulphate in said mixing zone to produce a mixture composed of water and aluminum sulphate, having a pH in the range of 1.5 to 6.5; (c) subsequently, the introduction of sodium aluminate in said mixing zone, to thereby increase the pH of said mixture to within the range of 7.5 to 12; (d) thereafter, the introduction of aluminum sulfate in said mixing zone to thereby reduce the pH of said mixture to within the range of 1.5 to 6.5; and (e) thereafter, the introduction of sodium silicate in said mixing zone to thereby increase the pH of said mixture within the range of 7.5 to 12; and recovering said precipitated solid from said mixture.

[0012] In yet another embodiment of the method of the invention, an amorphous silica-alumina composition is prepared, through: (a) the combination of water and aluminum sulfate to produce a first mixture having a pH in the range of 1.5 to 6.5; (b) adding sodium aluminate to said first mixture to produce a second mixture having a pH in the range of 7.5 to 12; (c) adding aluminum sulfate to said second mixture to produce a third mixture having a pH in the range of 1.5 to 6.5; (d) adding sodium silicate to said third mixture to produce a fourth mixture having a pH in the range of 7.5 to 12; (e) adding aluminum sulfate to said fourth mixture to produce a fifth mixture having a pH in the range of 1.5 to 6.5; (f) adding sodium aluminate to said fifth mixture to produce a sixth mixture having a pH in the range of 7.5 to 12; (g) adding aluminum sulfate to said sixth mixture to produce a seventh mixture having a pH in the range of 1.5 to 6.5; (h) adding sodium silicate to said seventh mixture to produce an eighth mixture having a pH in the range of 7.5 to 12; and (i) recovering a precipitated solid from said eighth mixture, where said precipitated solid consists of said amorphous silica-alumina composition.

[0013] Figure 1 shows the NMR spectrum in solid aluminum

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5/22 ( ²⁷ Al) of the amorphous silica-alumina powder of the invention.

[0014] Figure 2 is a diagram that details certain aspects of the method of the invention and associated equipment used to manufacture the amorphous silica-alumina composition of the invention.

[0015] Figure 3 shows the X-ray diffraction spectrum of the amorphous silicaalumina powder of the invention, a commercially available amorphous silica-alumina powder, and a bohemian powder.

[0016] The amorphous silica-alumina (ASA) composition of the invention has certain unique physical and catalytic properties that make it especially suitable for use alone as a catalyst or as a component of a composite catalyst. The process of the invention for the production of amorphous silica-alumina is a relatively simple and economical approach to the production of amorphous silica-alumina having certain unique physical and catalytic properties, and uses the production methodology called pH switching to produce the composition amorphous silica-alumina of the invention with its unique properties.

[0017] The process of the invention includes the preparation of a mixture containing water, an aluminum salt and a silicate, and the final formation of a precipitated solid by adding sequentially to, or mixing with the mixture in one or more series or alternations of an aluminum salt source that produces a low or low mixing pH, followed by the addition or mixing with the sodium aluminate or sodium silicate mixture that produces a high or increased mixing pH. This use of one or more pH changes in the formation of the silica-alumina precipitate is an essential feature of the process of the invention.

[0018] The meaning of the term used here is pH switching is that the pH of the preparation mixture is changed or recycled from a low acidic pH to a high alkaline pH, by adding an aluminum salt component to the preparation mixture. reduce the pH to the acid range of less than 7 followed by

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6/22 addition to the mixture of the preparation of sodium aluminate or sodium silicate, to raise the pH to the basic range of more than 7. After one or more pH changes, the resulting precipitated solid that is formed in the mixture of preparation is recovered from it. It is believed that the use of this method of alternating pH of the preparation produces the novel amorphous silica-alumina composition of the invention with its unique physical and catalytic properties.

[0019] One of the advantageous characteristics of the pH switching process of the invention is that it allows the use of a single vessel that defines a mixture or reaction zone, for the execution of the mixture and the precipitation reaction of the process. It appears that in several of the prior art processes for the production of silicaalumina, multiple processing tanks are required to conduct several process steps, such as, for example, a gelation step that can be performed in a different vessel one that is used to prepare a silica solution, and different vessels may also be used to perform certain other stages of the prior art processes. The process of the invention, on the other hand, features the use of a single mixing or reaction zone, in which the components of the mixture of the preparation of the process of the invention are added. This eliminates some of the manufacturing complexity that is often associated with prior art silica-alumina manufacturing processes that require the use of multiple mixing, reaction and transfer tanks or vessels.

[0020] Another of the advantages of the pH switching process of the invention, is that it can significantly reduce the total time required for the preparation and precipitation for the production of the final suspension from which the precipitated solid that constitutes the amorphous silica-alumina is recovered. of the invention process. The time taken to add the component preparation mixture to each step of one or more pH changes can be minimized to produce a short total precipitation time for the preparation of the final suspension which includes the

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7/22 precipitated solid. In several cases, the time taken to prepare a final suspension can be significantly shorter than that of prior art processes.

[0021] In general, the method of the invention initially includes the combination of water and aluminum sulfate in such quantities that produce a mixture that has a pH that is acidified, ie, a pH less than 7. It is desirable that the The pH of this initial mixture is in the range of 1.5 to 6.5, and preferably of 2 to 6. More preferably, the initial mixture should have a pH that is in the range of 2.5 to 5.5, and especially preferably, from 3.1 to 5.1. As soon as this initial mixture is formed, the next step in the method includes adding an amount of sodium aluminate or sodium silicate to the initial mixture in an amount such that it increases the pH of the resulting mixture so that it is alkaline, ie , a pH greater than 7. It is desirable for this pH to be in the range of 7.5 to 12, and preferably, 8 to 11.5. Most preferably, the pH is in the range of 8.5 to 11. These two process steps, which include a change in the pH of the mixture after the addition of aluminum sulfate to reduce the pH of the mixture, followed by the separate addition of sodium aluminate or sodium silicate to increase the pH of the mixture, are together considered here to be a pH shift.

[0022] The time spent between the two steps of adding the pH switching method need not be long, but it only needs to be long enough to allow substantial mixing of the added components. In the event that the components are combined together within a single mixing zone, it is desirable that the mixing time is sufficient to allow mixing of the components to produce a substantially homogeneous preparation mixture. An important feature of the method of the invention is the application of multiple pH alternations in the preparation of the preparation mixture which becomes a final suspension of the silica and alumina cogel, or, in another

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8/22 form, a suspension of a precipitated solid consisting of silica-alumina.

[0023] In a more specific embodiment of the method of the invention, the components of the preparation mixture are combined together within a single mixing or reaction vessel which defines a mixing or reaction zone and which produces means for the mixing or reaction of the components, in order to finally form a suspension of precipitated solid that constitutes the silica-alumina of the invention. The mixing or reaction vessel may be any suitable vessel and associated equipment known to those skilled in the art, including a vessel that is equipped with means for agitating the contents of the vessel, such as a rotating rotor, to produce the mixture and dispersion of the components therein and suspending and dispersing the precipitate solids from the mixture of the preparation of the method of the invention. The vessel may also be operatively equipped with means for exchanging heat with the vessel contents to produce temperature control of the vessel contents.

[0024] In this embodiment of the process of the invention, which uses a single mixing zone, water and aluminum sulphate are first introduced into the mixing zone in quantities and proportions to produce a mixture that consists of water and aluminum sulphate, having a pH that is in the range of 1.5 to 6.5, preferably from 2 to 6, and more preferably, from 2.5 to 5.5, and especially from 3.1 to 5.1. After the mixing of the water and the aluminum sulphate is completed, sodium aluminate is then introduced into the mixing zone and it is mixed with the mixture within it in an amount that increases the pH of the mixture to within the range of 7, 5 to 12, preferably from 8 to 11.5, and more preferably, from 8.5 to 11.

[0025] It is desirable to minimize the time required for mixing the components of each step of adding the method, only for that which is required to produce a homogeneous mixture within the mixing zone. Although the mixing time may vary, depending on the type of equipment used, the size

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9/22 of equipment, and other factors, the time required to combine, mix and disperse the components, should generally be in the range of 1 to 30 minutes per addition step.

[0026] After the end of the pH change described above, the aluminum sulphate is introduced back into the mixing zone and is mixed with the mixture of the preparation contained therein in an amount that reduces its pH to within the range of 1 , 5 to 6.5, preferably 2 to 6, more preferably 2.5 to 5.5, and especially preferably 3.1 to 5.1. This step is followed by the introduction of sodium silicate in the mixing zone and mixing it with the mixture of the preparation in it in an amount that increases the pH of the mixture to within the range of 7.5 to 12, preferably from 8 to 11.5, and more preferably, 8.5 to 11, which completes the second pH switch.

[0027] The precipitate solids formed contained in the preparation mixture after the end of the second pH change may be recovered from the remaining liquid, which is sometimes referred to as mother liquor, by any of the methods known to those skilled in the art; however, it is preferable to continue the sequence of pH changes before recovering the precipitated solids that are formed in the final suspension of the mixture of the preparation of the process of the invention.

[0028] Therefore, after the end of the second pH change, the aluminum sulphate is introduced again into the mixing zone and is mixed with the mixture within it in an amount that reduces the pH of the mixture to within the range of 1.5 to 6.5, preferably 2 to 6, more preferably 2.5 to 5.5, and especially preferably 3.1 to 5.1. This step is followed by the introduction of sodium aluminate in the mixing zone and mixing it with the preparation mixture in it, in an amount that increases the pH of the preparation mixture to within the range of 7.5 to 12, from preferably from 8 to 11.5, and more preferably,

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10/22 from 8.5 to 11, to complete the third pH switch.

[0029] After the end of the third pH switch, the aluminum sulphate is again introduced into the mixing zone and is mixed with the preparation mixture in it, in an amount that reduces the pH of the preparation mixture to within the range from 1.5 to 6.5, preferably from 2 to 6, more preferably from 2.5 to 5.5, and especially preferably from 3.1 to 5.1. This step is followed by the introduction of sodium silicate in the mixing zone and mixing it with the mixture of the preparation in it, in an amount that increases the pH of the mixture of the preparation to within the range of 7.5 to 12, from preferably from 8 to 11.5, and more preferably from 8.5 to 11, to complete the fourth pH changeover. After the fourth pH changeover ends, the precipitated solids formed contained in the final suspension of the preparation mixture are recovered from the remaining liquid.

[0030] The temperature conditions under which the preparation mixture is formed within the mixing zone of the process of the invention can affect the properties of your final amorphous silica-alumina product with higher preparation temperatures tending to produce material that is more crystalline and lower preparation temperatures tending to produce material that is more amorphous. However, there may be limits on the temperature conditions required to produce a desired product. Therefore, it is desirable to control the mixing and reaction temperatures of the process steps within certain defined temperature ranges. Generally, the mixing and reaction temperatures for each of the pH changes should be in the range of 20 ° C to 90 ° C, preferably from 30 ° C to 80 ° C, and more preferably, 40 ° C to 70 ° C. It is especially desirable for the mixing and reaction of the components to take place as close to the isothermal conditions that are feasible with the use of typical commercial mixing and reaction process equipment. In addition to controlling the pH of the mixture of the various steps of adding each of the pH changes, it is also desirable to combine

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11/22 components in such quantities as to produce a final suspension mixture from which precipitated solids are recovered, which has a solids content of 1 to 30% by weight (% by weight), based on the total weight of the preparation mixture . Preferably, the proportion of solids in the final mixture of the suspension is in the range of 2 to 20% by weight, and more preferably, from 3 to 15% by weight.

[0031] To produce the desired weight percentage of solids precipitated in the final suspension of the process of the invention, the relative amounts of aluminum sulphate, sodium aluminate and sodium silicate for each of the pH changes are adjusted within certain ranges desired. For example, in pH changes involving the addition of aluminum sulphate followed by the addition of sodium aluminate, the weight ratio between sodium aluminate and aluminum sulphate for the components added to the preparation mixture, in general, should be in the range from 0.1 to 1.5, more preferably from 0.3 to 1.1, and more preferably, from 0.5 to 0.9. In pH changes involving the addition of aluminum sulphate followed by the addition of sodium silicate, the weight ratio between sodium silicate and aluminum sulphate should generally be in the range of 0.5 to 5, but preferably , from 1 to 4, and more preferably, from 1.5 to 3.

[0032] The way in which aluminum sulfate, sodium aluminate and sodium silicate are added to the mixture of the process preparation of the invention may be as a dry solid or as an aqueous solution of the specific component.

[0033] Any suitable method known to those skilled in the art for separating precipitated solids from the remaining fluid of the suspension mixture or final preparation may be used to recover the precipitated solid. Such methods include gravity separation, pressure separation, and vacuum separation, and may include the use of equipment, such as, for example, belt filters, plate-and-frame filters, and rotary vacuum filters. .

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12/22 [0034] The precipitated filtered solids, or filter cake, can be washed with water to remove impurities, such as sodium and sulfate salts. The amount of water used to wash the precipitated solids can be any amount that adequately produces a washed powder having a pH that is within the desired range of 2 to 7, and preferably 2.5 to 5.5. The weight ratio of water to dry powder used in a single washing step can be in the range of 0.1: 1 to 100: 1, preferably 0.5: 1 to 50: 1. One or more washing steps may be used to wash the filtered precipitated solids. The washed precipitate may also be resuspended and spray dried using any of the suitable spray drying methods known to those skilled in the art to produce a spray dried powder.

[0035] The spray-dried powder may additionally be processed through drying or calcination, or both, or it, or the dried and / or calcined powder, may be composed of other components to form a constituted composition. The spray-dried powder may be air-dried or any other suitable atmosphere under drying conditions at a drying temperature in the range of 50 ° C to 200 ° C, preferably from 60 ° C to 180 ° C. The spray-dried powders, preferably after being further dried, can be calcined under suitable calcination conditions, especially in an oxygen-containing atmosphere, such as air, at a calcination temperature in the range of 275 ° C at 1000 ° C, preferably from 300 ° C to 800 ° C, and more preferably, from 350 ° C to 600 ° C.

[0036] The amorphous silica-alumina of the invention, alone or when composed with other components to form a constituted catalytic composition, can be useful in a wide variety of hydrocarbon processes, including, for example, hydrocracking, hydrotreating (e.g. hydrodesulfurization, hydrodeshydrogenation and hydrodesmetallization), hydro finishing, isomerization, polyPetition 870170065052, from 9/1/2017, p. 23/42

13/22 merization, catalytic degreasing, and catalytic cracking. Possible raw materials that can be processed or treated using the amorphous silica-alumina of the invention include hydrocarbons that boil in the boiling range of gasoline, distilled hydrocarbons, including diesel and kerosene, gas oils, including atmospheric diesel and diesel vacuum, atmospheric or vacuum residues, de-asphalted oils, catalytically cracked recycled oils, coking gas oils and other thermally cracked oils and oils.

[0037] The recovered precipitate is a unique silica-alumina composition, which is highly amorphous, because it contains very little alumina which is crystalline. The amount of crystalline alumina in the silica-alumina composition is indicated by its characteristic powder X-ray diffraction (XRD) pattern, which has a significant high of XRD peaks that are representative of the various phases of crystalline alumina. Generally, the amount of alumina that is in the crystalline phase contained in the amorphous silicaalumina is less than 10% by weight of the total weight of the silicaalumina composition. More specifically, the amorphous silica-alumina composition has less than 8% by weight of crystalline alumina, and more specifically, and it has less than 5% by weight of crystalline alumina.

[0038] The amorphous silica-alumina composition can have a silica content that is in the range of 10 to 90% by weight, with the weight percentage being based on the total dry weight of the silica-alumina composition. The preferred silica content, however, is in the range of 25 to 75% by weight, and more preferably, the silica content is in the range of 40 to 60% by weight. Alumina may be present in the silica-alumina composition in an amount in the range of 10 to 90% by weight, more specifically, from 25 to 75% by weight, and more specifically, from 40 to 60% by weight.

[0039] An advantageous property of the amorphous silica-alumina composition is that it has a relatively high proportion between its pore volume that is contained in its large pores and the pore volume that is contained in

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14/22 your small and medium pores. A measure of this property is the proportion of pore volume (cm ³ / g) contained in the pores of the amorphous silica-alumina composition having a pore diameter less than 2.15x10 ^-7 m (2150 À) (A) and the pore volume contained in the pores of the amorphous silica-alumina composition having a pore diameter of less than 2.1x10 ^-8 m (210 À) (B). This A-to-B (A / B) ratio, in general, should exceed 2.2, and preferably, the A / B ratio exceeds 2.4, and more preferably, the A / B ratio exceeds 2 , 5.

[0040] The references here to the total pore volume are to the pore volume, as determined using the standard test method for determining the pore volume distribution of catalysts using Mercury Intrusion Porosimetry, ASTM D 4284- 88, at a maximum pressure of 4000 bar (400000 kPa), considering a surface tension for mercury of 0.00484 N / cm (484 dynes / cm) and a contact angle with 140 ° amorphous silica-alumina .

[0041] Another feature of the amorphous silica-alumina composition is that it has a significantly high surface area and total pore volume. Its surface area can be in the range of 190 m ² / g to 400 m ² / g, but more specifically, it is in the range of 200 m ² / g to 350 m ² / g, and more specifically, 225 m ² / ga 325 m ² / g. The total pore volume of the amorphous silica-alumina composition is in the range of 0.8 cm ³ / g to 1.3 cm ³ / g, more specifically, from 0.9 cm ³ / g to 1.2 cm ³ / g , and more specifically, from 0.95 cm ³ / g to 1.1 cm ³ / g.

[0042] The amorphous silica-alumina composition of the invention is further characterized by its NMR spectrum in the solid state ( ²⁷ Al) of aluminum. The NMR spectrum in the solid aluminum state of the amorphous silica-alumina composition has three significant peaks: a first peak located around 65 ppm on the chemical alternation scale, representing aluminum sites in tetrahedrals; a second peak located around 30 ppm on the chemical alternation scale, representing octahedral aluminum sites. These chemical alternations are referred to chloride

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15/22 0.0 ppm aqueous aluminum. The alternations of the peaks mentioned above can be influenced by the acidity and second-order quadripolar interaction experienced by the respective aluminum cores.

[0043] Figure 1 shows a representative NMR spectrum in the solid state of ²⁷ Al for the amorphous silica-alumina of the invention. An important feature of this spectrum is that it includes a strong penta-coordination peak, which represents the presence of penta-coordinated aluminum (Al). And the penta-coordination peak and its resistance are an indication of the disorder and defects in the structure of amorphous silicaalumina and it is believed that the penta-coordinated aluminum contained in the amorphous silica-alumina composition of the invention increases its acidity. increases catalytic activity when used in catalytic applications. Generally, the penta-coordinating peak should be relative in size to the other aluminum peaks that represent the presence of penta-coordinated aluminum in an amount greater than 30% of the total of the three types of aluminum represented by the three peaks of the spectrum NMR. More specifically, the strong coordination peak of the NMR spectrum in the solid state of ²⁷ Al of amorphous silica-alumina must be greater than 35% of the total of the three types of aluminum, and more specifically, it must be greater than 40% of the total of the three types of aluminum.

[0044] As mentioned here, the NMR spectrum of the amorphous silicaalumina composition is that which is generated using any standard nuclear magnetic resonance (NMR) spectroscopy methodology known to those trained in the art of using NMR techniques for characterize structural configurations of solid materials. The determination of the NMR spectrum of the amorphous silica-alumina composition can be done using any suitable instrumentation and equipment that produces a spectrum that is substantially similar to that which can be produced using the NMR spectrometer manufactured and marketed by Varian, Inc. , from Palo Alto, California, as

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16/22 the Varian NMR 400-MR spectrometer, using a 5 mm high power solid state NMR sensor from Doty Scientific, Inc. of Columbia, South Carolina. The samples are placed in a 5 mm silicon nitride (Si3N4) rotor and rotated at 13 to 16 kHz (780,000 to 960,000 rpm) in a dry nitrogen atmosphere at room temperature. The stator housing is adjusted to be at a magic angle with the external magnetic field to minimize the widening caused by the random orientation of the individual cores with reference to the external magnetic field. The resonance frequency for the aluminum core at this field resistance is 104.3 MHZ. The spectrum width of 0.5 MHz, a pulse width of 1.0 micro-seconds, and a recycle delay of 0.3 seconds are used as conditions for the experiment.

[0045] An embodiment of the pH shifting method of the invention for producing a silica-alumina composition, includes four pH shifts and is now described with reference to figure 2.

[0046] Figure 2 shows an equipment system 10 that is responsible for applying the pH alternation method for the production of an amorphous silica-alumina product having certain unique physical properties, including having a high macro-porosity and presenting a typically strong NMR penta-coordination peak of aluminum that represents more than 30% of the total aluminum in the composition. Equipment system 10 includes a mixing or reaction vessel 12, which defines a mixing or reaction zone and provides a means for mixing or reacting the components of the preparation mixture 14 contained within the mixing or reaction vessel 12.

[0047] The mixing or reaction vessel 12 is preferably equipped with a stirring device 16, which could include a rotating rotor 18 that provides means for mixing and dispersing the components of the preparation mixture 14. The mixing vessel mixture or reaction 12 can also be operationally equipped with

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17/22 a heat transfer coil or heat transfer jacket 20, which provides means for exchanging heat with the mixture of preparation 14 of the mixing or reaction vessel 12 to provide control of its temperature.

[0048] In the first pH changeover of the method, water and aluminum sulfate are introduced through the transfer method 22 into the mixing or reaction vessel 12 to form a first mixture of the mixture from preparation 14. The relative quantities of each one of these components are adjusted to produce the first mixture, so that it has a pH in the range of 1.5 to 6.5, while keeping in mind the target solids percentage of the final mixture of the mixture mixture. Preparation 14 and the target weight percentages of silica and alumina to be contained in the precipitated solids of the final mixture of the suspension.

[0049] The transfer method 22 is responsible for introducing the components into the mixing or reaction vessel 12 and may be through the use of any suitable means, including duct means or manual means or conveyor belt means, or through any other means suitable means for transporting the components and introducing them into the mixing or reaction vessel 12. Therefore, the line detailing transfer method 22 represents merely the introduction of the various components of the preparation mixture 14 that are formed within the vessel mixing or reaction 12.

[0050] After the introduction of aluminum sulphate in the mixing or reaction vessel 12, subsequently, sodium aluminate, using transfer method 22, is added and mixed with the first mixture of preparation mixture 14 in such an amount that it produces a second mixture of preparation mixture 14 having a pH in the range of 7.5 to 12, to complete the first pH changeover of the method.

[0051] In the second pH alternation of the method, aluminum sulfate is added 870170065052, from 01/09/2017, p. 28/42

18/22 in the second mixture of preparation mixture 14 in such an amount as to produce a third mixture of preparation mixture 14 that has a pH in the range of 1.5 to 6.5, while keeping in mind the percentage of target solids of the final mixture of the preparation mixture suspension 14 and of the target weight percentages of silica and alumina to be contained in the precipitated solids of the mixture of the final suspension. After the formation of the third mixture of preparation mixture 14, sodium silicate is added to the third mixture in an amount such that it produces a fourth mixture of preparation mixture 14 that has a pH in the range of 7.5 to 10 at the same time. keeping in mind the target solids percentage of the final suspension of the mixture of preparation 14 and the target weight percentages of silica and alumina to be contained in the precipitated solids of the final suspension mixture. This completes the second pH shift of the method.

[0052] In the third pH alternation of the method, aluminum sulfate is added to the fourth mixture, in order to reduce the pH of the mixture of preparation 14 and thus to produce a fifth mixture having a pH in the range of 1.5 to 6 , 5, while keeping in mind the target percentage of solids of the final suspension in mixture of preparation mixture 14 and the target percentages by weight of silica and alumina to be contained in the precipitated solids of the mixture of the final suspension. After the formation of the fifth mixture of preparation mixture 14, sodium aluminate is added to the fifth mixture, thereby raising the pH of preparation mixture 14 and thereby producing a sixth mixture having a pH in the range of 7.5 to 12, while also keeping in mind the target solids percentage of the final suspension of the mixture of preparation 14 and the target weight percentages of silica and alumina to be contained in the precipitated solids of the final suspension mixture. This completes the third pH switch of the method.

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19/22 [0053] In the fourth pH alternation of the method, aluminum sulfate is added to the sixth mixture, in order to reduce the pH of the preparation mixture 14 and thus to produce a seventh mixture having a pH in the range of 1, 5 to 6.5, while keeping in mind the target solids percentage of the final suspension mixture of preparation mixture 14 and the target weight percentages of silica and alumina to be contained in the precipitated solids of the final suspension mixture . After the formation of the seventh mixture of preparation mixture 14, the sodium silicate is then added to the seventh mixture to thereby raise the pH of preparation mixture 14 and thereby produce an eighth mixture having a pH in the range of 7.5 to 12, while keeping in mind the target percentage of solids of the final suspension mixture of preparation mixture 14 and the target weight percentages of silica and alumina to be contained in the precipitated solids of the final suspension mixture. This completes the fourth pH shift of the method.

[0054] In an embodiment of the pH alternation method, the final suspension from which the precipitated solid is recovered, may be the eighth mixture of preparation mixture 14. Therefore, the final suspension of the mixing or reaction vessel 12, which in this case it is the eighth mixture of the preparation mixture 14, it is transferred from the mixing or reaction vessel 12, through line 24, for further processing, to recover the precipitated solids. Although the additional processing or equipment steps are not detailed in figure 12, it is noted that the final suspension can be filtered using any of the methods or means known to those trained in the art, as mentioned here. The filtered precipitated solids may preferably be washed with water to remove impurities and spray drying. The recovered precipitated solids can be dried or calcined, or both.

[0055] The following example is presented to further illustrate certain Petition 870170065052, of 9/1/2017, p. 30/42

20/22 aspects of the invention, but should not be considered as limiting the scope of the invention.

Example 1 [0056] The description in this example 1 illustrates the pH switching method of the invention for preparing the amorphous silica-alumina composition of the invention. Data on physical properties related to the amorphous silicaalumina product produced by the pH alternation method are also presented.

[0057] The amorphous silica-alumina powder of the invention was prepared using a pH alternating precipitation process that includes four pH alternations conducted in a tank called a reserve. In the preparation process, a quantity of residual water is first introduced into the reserve tank. Subsequently, aqueous solutions of aluminum sulfate, sodium alumina, and sodium silicate were added, in a sequence in the order and relative quantities shown in table 1, in the liquor contained in the reserve tank, to produce the pH of the liquor as also indicated in table 1. Four pH changes were performed at a temperature of approximately 155 ° C and a constant stirring speed of 43 rpm. The addition and mixing time for each step was approximately 5 minutes. At the end of the last (fourth) pH change, the solids content of the final liquor, or suspension, was around 6% by weight (6% by weight). These solids were recovered and washed. The recovered and washed solids were washed again and then spray-dried to form the final amorphous silica-alumina powder.

Table 1 - Order of addition and quantities of the reaction components in the reserve ring and the pH of the. liquor resulting from each stage

PH switching Stage Component added Relative mass pH of the liquor n ° onado of the component added because of the addition

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1 Residual water 19039 First change 2 Aluminum sulfate 1777 3.2 pH 3 Sodium aluminate 974 8.3 Second change 4 Aluminum sulfate 611 4.1 pH 5 Sodium silicate 1784 9.1 Third alternative 6 Aluminum sulfate 1823 3.6 pH 7 Sodium aluminate 1211 9.1 Fourth alternation 8 Aluminum sulfate 600 6.5 pH 9 Sodium aluminate 1802 9.6

[0058] The amorphous silica-alumina powder, spray-dried, which was calcined at 538 ° C (1000 ° F) was analyzed using solid state NMR ( ²⁷ Al) with high speed magic angle (14 to 15 kHz ) of spiraling the sample. The NMR ²⁷ Al spectrum of the amorphous silica-alumina powder that was determined according to the methodology described above here, is shown in figure 1. As can be seen by observing this NMR spectrum, in addition to the reference peak, there are three other peaks at locations of approximately 3 ppm, 30 ppm, 65 ppm on the chemical alternation scale. The peak at the 65 ppm site corresponds to the tetrahedral aluminum sites on the lattice, the peak at the 30 ppm site corresponds to the aluminum penta-coordination site, and the peak at the 3 ppm site corresponds to the octahedral aluminum site of the structure in spiral. The NMR spectrum shows that a significant amount of aluminum is present in the form of pentacoordinated aluminum, when compared to other forms of aluminum.

[0059] Spray dried silica-alumina powder and comparative samples of bohemian alumina and a commercial amorphous silica-alumina product used by

Criterion Catalyst Company in the manufacture of certain of its hydroprocessing catalysts, each was analyzed using the standard powder X-ray diffraction methodology. The spectra of these three compositions are

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22/22 shown in figure 3. As can be seen, the XRD spectrum of samples of bohemian and commercial silica-alumina show significant crystallinity containing numerous XRD peaks that are representative of the crystalline components contained in the compositions. On the other hand, in comparison, the XRD spectrum of the silica-alumina powder of the invention shows the presence of very little crystalline material.

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1/4

Claims (10)

1. Method for producing an amorphous silica-alumina composition, having a silica content of 40 to 75% by weight, with weight based on the total dry weight of the silica-alumina composition, having less than 10% by weight of crystalline alumina, the silica-alumina composition still having an A / B ratio exceeding 2.2, where A in said ratio is the volume of pores contained in the pores of said composition having a pore diameter less than 2150 À and B in said reason is the volume of pores contained in the pores of said composition having a pore diameter less than 210 À, said method CHARACTERIZED by the fact that it comprises: (a) combining, within a mixing zone, water and aluminum sulfate, to produce a mixture having a pH in the range of 1.5 to 6.5; (b) subsequently, increasing the pH of said mixture to within the range of 7.5 to 12, by adding sodium silicate to said mixture within said mixing zone, in which the weight ratio of sodium silicate to aluminum sulfate is in the range of 0.5 to 5; thus, producing a final paste mixture; and (c) recovering a precipitated solid from said mixture in said mixing zone, wherein the mixture has a solids content of 1 to 30% by weight, based on the total weight of the prepared mixture, and wherein said precipitated solid comprises said silica-alumina composition. 2. Method, according to claim 1, CHARACTERIZED by the fact that it additionally comprises, before the recovery step (c): (d) after the step of increase (b), reduce the pH of said mixture to within the range of 1.5 to 6.5, by adding aluminum sulfate to said mixture within said mixing zone; and (e) subsequently, increase the pH of said mixture to within the range of 7.5 to 12, by adding sodium aluminate to said mixture within the Petition 870170065052, of 9/1/2017, p. 34/42 2/4 said mixing zone, and in which the weight ratio of sodium aluminate to aluminum sulfate of the components added in steps (d) and (e) is in the range of 0.1 to 1.5. 3. Method, according to claim 2, CHARACTERIZED by the fact that it additionally comprises: (f) after the step of increasing (e), reducing the pH of said mixture to within the range of 1.5 to 6.5, by adding aluminum sulfate to said mixture, within said mixing zone; and (g) thereafter, increasing the pH of said mixture to within the range of 7.5 to 12, by adding sodium silicate to said mixture, within said mixing zone, in which the weight ratio of the silicate of sodium for the aluminum sulfate of the components added in steps (f) and (g) is in the range of 0.5 to 5. 4. Method for producing an amorphous silica-alumina composition, having a silica content of 40 to 75% by weight, with the weight based on the total dry weight of the silica-alumina composition, having less than 10% by weight of crystalline alumina, the silica-alumina composition still having an A / B ratio exceeding 2.2, where A in said ratio is the volume of pores contained in the pores of said composition having a pore diameter less than 2150 À and B in said reason is the volume of pores contained in the pores of said composition having a pore diameter less than 210 À, said method CHARACTERIZED by the fact that it comprises: to form within a mixing zone a solid precipitate comprising silica-alumina through: (a) introducing water into said mixing zone; (b) introducing aluminum sulfate into said mixing zone in order to produce a mixture comprising water and aluminum sulfate, having a pH in the range of 1.5 to 6.5; (c) subsequently, introduce sodium aluminate into said mixing zone, Petition 870170065052, of 9/1/2017, p. 35/42 3/4 to thereby increase the pH of said mixture to within the range of 7.5 to 12, and in which the weight ratio of sodium aluminate to aluminum sulfate of the components added in steps (b) and (c ) is in the range of 0.1 to 1.5; (d) subsequently, introducing aluminum sulfate into said mixing zone, in order to thereby reduce the pH of said mixture to within the range of 1.5 to 6.5; and (e) subsequently, introducing sodium silicate into said mixing zone, in order to thereby increase the pH of said mixture to within the range of 7.5 to 12, and in which the weight ratio of sodium silicate to sulfate The aluminum content of the components added in steps (d) and (e) is in the range of 0.5 to 5; thus, producing a final paste mixture; and recovering said precipitated solid from said mixture which has a solids content of 1 to 30% by weight, based on the total weight of the prepared mixture. 5. Method, according to claim 4, CHARACTERIZED by the fact that it additionally comprises, before the recovery step: (f) after step (e), introduce aluminum sulfate into said mixing zone, to thereby reduce the pH of said mixture to within the range of 1.5 to 6.5; (g) subsequently, introduce sodium aluminate into said mixing zone, in order to increase the pH of said mixture to within the range of 7.5 to 12, in which the weight ratio of sodium aluminate to aluminum sulfate the components added in steps (f) and (g) are in the range of 0.1 to 1.5; (h) subsequently, introducing aluminum sulfate into said mixing zone, in order to thereby reduce the pH of said mixture to within the range of 1.5 to 6.5; and (i) subsequently, introduce sodium silicate in the said mixing zone, in order to increase the pH of the said mixture within the range of 7.5 to Petition 870170065052, of 9/1/2017, p. 36/42 4/4 12, in which the weight ratio of sodium silicate to aluminum sulfate of the components added in steps (h) and (i) is in the range of 0.5 to 5. 6. Method according to any one of claims 1 to 5, CHARACTERIZED by the fact that amorphous silica-alumina has the characteristic of a penta-coordinated peak in the NMR spectrum, which has a size relative to the other aluminum peaks of in order to represent the presence of penta-coordinated aluminum in an amount greater than 30% of the total of the three types of aluminum. Method according to any one of claims 1 to 6, CHARACTERIZED by the fact that amorphous silica-alumina has a surface area of 190 m ² / g to 400 m ² / g, preferably 200 m ² / g to 350 m ² / g and more preferably 225 m ² / g to 325 m ² / g. 8. Method according to any one of claims 1 to 7, CHARACTERIZED by the fact that amorphous silica-alumina has a total pore volume of 0.8 cm ³ / g to 1.3 cm ³ / g, preferably 0 , 9 cm ³ / g to 1.2 cm ³ / g, more preferably 0.95 cm ³ / g to 1.1 cm ³ / g. 9. Method according to any one of claims 1 to 8, CHARACTERIZED by the fact that the mixing and reaction temperatures of steps (b) to (e) are in the range of 20 ^o C to 90 ^o C, preferably 30 ^o C to 80 ^o C, more preferably 40 ^o C to 70 ^o C. 10. Method according to any one of claims 1 to 9, CHARACTERIZED by the fact that the mixing and reaction take place as close to isothermal conditions as possible. Petition 870170065052, of 9/1/2017, p. 37/42 1/3 Petition 870170065052, of 9/1/2017, p. 39/42 2/3 Petition 870170065052, of 9/1/2017, p. 40/42 3/3 Counter / sec